The Hybridoma Library/Monoclonal Antibody Production Shared Resource develops new monoclonal antibodies and provides NCCC investigators with quality-controlled monoclonal antibodies (mAbs) as purified proteins and/or supernatants from hybridoma cell lines that have been obtained from the ATCC or from individual investigators. This facility maintains characterized and quality-controlled stocks of supernatants and monoclonal antibodies from over 100 cell lines. It is especially cost-effective for studies that require only a small sample of a given antibody that, purchased commercially, would result in a charge to individual grants of $250 to $500 per antibody. This Resource also advises investigators on the production and purification of large quantities of antibodies as needed. The Resource has recently been expanded to carry out hybridoma production for NCCC investigators. The entire procedure, beginning with animal immunizations and continuing up to and including subcloning of selected hybrids, is being carried out by the newly expanded facility. Individual investigators are currently being charged approximately one-third the cost of commercial production. Other services, such as in vitro antibody scale-up and purification, are being considered. During the past year, this Resource was used almost exclusively by NCCC investigators; in the case of previously existing antibodies, there previously was no charge-back system for supplying antibodies, which often come from patented cell lines. With the provision of a new service to produce monoclonal antibodies, for which there is a charge-back, it is estimated that the Resource will save investigators more than $200,000 per year over the commercial cost of comparable antibodies and services.